Dr. Oz explains how a heart attack occurs.

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Question 9: What day and time do most people have heart attacks?
A) Monday morning
B) Tuesday afternoon
C) Saturday night
D) Sunday brunch

The correct answer is A.

As the blood courses through an artery in your heart, plaque can build up on the walls. Sometimes, the plaque ruptures, leaving a raw surface exposed, Dr. Oz says. Platelets in the blood begin to form a scab over the rupture, which can lead to a blockage that causes a heart attack.

"That's why Monday mornings are worrisome to us, because it's a time of change, a time of stress," he says. "It's a time when that plaque is more likely to rupture and result in a heart attack. It doesn't take days to occur. It takes minutes, maybe hours to occur."